The present invention is directed to a method of routing radio telephone calls of an ad-hoc, peer-to-peer radio system, and, in particular, to such an ad-hoc, peer-to-peer radio system disclosed in copending application Ser. No. 09/705,588, filed on Nov. 3, 2001, entitled “Methods and Apparatus for Coordinating Channel Access to Shared Parallel Data Channels”, now U.S. Pat. No. 6,404,756, which application is incorporated by reference herein. The network system having coordinating channel access to shared parallel data channels via a separate reservation channel of U.S. Pat. No. 6,404,756 is directed to a network system, such as radio network, where each node, or radio terminal, of the network is capable of serving as a node or hop of a routing path of a call from another, or to another radio terminal. In that system, communication between nodes or radio terminals is achieved using Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol with the addition of multiple parallel data channels serviced by one reservation channel. By dedicating a separate reservation channel for the multiple parallel data channels, collision-free access by all of the competing nodes or terminals of the service group of the network is greatly reduced. Communications between terminals or nodes is set up by information exchanged on the separate reservation channel, which information includes all of the call set-up information, such as data channel desired to be used for transferring voice, video or data, the desired power level of at least initial transmission, messaging such as Request-to-Send (RTS), Clear-to-Send (CTS), Not-Clear-to-Send (NCLS), Acknowledgment (ACK) for indicating reception of the transmitted call, Non-Acknowledgment (NACK) for indicating improper reception of the call, etc. in this system, in order to further ensure fast, adequate and collision-free transmission and reception, besides a primary modem typically provided with the transceiver of each node or terminal, a secondary modem is also provided which is dedicated to the reservation channel when the primary modem of the transceiver is occupied, such as when sending out data on a data channel. This system also provides for collision free transmission and reception between nodes or terminals by transmitting the reservation and data channels in time slots of time frames, with the information as to which time slot is to be used being included in the messaging transmitted by the reservation channel. Such a format not only provides collision-free transmission, but also allows for Quality-of-Service (QOS) for different types of Class-of-Service (COS), Thus, not only may voice and video be transmitted, besides data, but voice and data transmission may be prioritized, so that when competing calls vie for a data channel, the delay-dependent voice or video transmissions will take precedence. This prioritization is accomplished by assigning prioritized calls for transmission in earlier time slots of a time frame.
Voice data transmission is allowed a bit error rate (BER) of 10-3 bits/sec., data cannot have a BER in excess of 10-12 bits.sec., and video may have a BER of between 10-6–10-7 bits/sec. Voice should be transmitted with a delay that does not exceed 150 mil.sec. before noticeable degradation occurs.
The network system disclosed in U.S. Pat. No. 6,404,756 ensures that every node or terminal of a service set of terminals has the most information regarding all of other terminals of that service set, so that the choice of data channel to be used, any required delay is transmitting the call, information on power level, and the like, are checked and updated by each terminal by a practically continuous monitoring of the reservation channel, and utilizes protocol that provides collision-free channel access, which also emphasizes improving geographic reuse of the frequency spectrum.
In U.S. Pat. No. 5,943,322 —Mayer, et al., which patent is incorporated by reference herein, there is disclosed a radio system is for use in battlefield conditions. The ad-hoc, peer-to-peer radio system of this patent does not have, nor require, a base station, as conventional cellular systems, personal communications system (PCS), and the like, require; instead, each radio terminal forming part of the ad-hoc, peer-to-peer radio system may alternatively serve as a base station, in addition to being an ordinary link terminal of the radio system, whereby, if one such terminal serving as a base station should for some reason become inoperative, another terminal may take over and serve as the base station. The ad-hoc, peer-to-peer radio system of this patent is based on a transport-mechanism using a time division duplex (TDD) technique in a code division multiple access (CDMA) system. Time Division Duplex (TDD) is a way of maximizing the bits/hz/km2. Such a system not only may be used for providing commercial voice, but is also quite suited to both transmission and reception of data and video services.
Time Division Duplex (TDD) systems are typically used for packet data systems as they make much more efficient use of the available bandwidth, in order to deliver a much higher effective data rate to the end user. TDD is typically used in fixed wired solutions or point-to-point wireless systems because it has its own spectrum limitations. TDD systems, however, have not been deployed for voice systems.
In copending provisional application Ser. No. 60/248,182, which application is incorporated by reference herein, there is disclosed an ad-hoc, peer-to-peer radio system for use as a stand-alone system that is also connected to a cellular network and/or landline. The ad-hoc mobile radio networking system thereof is capable of receiving and transmitting voice, data and video calls through any number of different types of telecommunication networks, such as the PSTN, the Internet, and the like, besides the cellular and next-generation cellular networks.
In any ad-hoc, peer-to-peer radio system, a critical consideration is the status and life of the battery of each terminal forming a part of the system. With the arrival of laptop computers, portable digital assistants (PDAs) and high-tech cellular phones, consumers are beginning to request mobile data services in addition to traditional voice services. Such devices are in use much more than traditional cellular phones, and, therefore, deplete their limited-life batteries more quickly. The ad-hoc, peer-to-peer system disclosed in the above-mentioned priority, provisional application Ser. No. 60/248,182, depletes batteries even more quickly, since each terminal can also serve as a router and relay for other terminals of the system, in order to extend the range or provide alternate routes to destinations. The ability to limit the use of the battery, therefore, is a very important element and consideration of that system.
In commonly-owned U.S. application Ser. No. 09/815,157, filed on Mar. 22, 2001, entitled “Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel”, now U.S. Pat. No. 6,807,165, which application is incorporated by reference herein, there is disclosed a protocol method and algorithm for ad-hoc network system that is based on least-energy routing of calls from and between network radio terminals. In simple terms, the major component of the routing decision is to choose the route to the destination that uses the least amount of energy over the complete route. The major reason for this is that least-energy routing minimizes the radiated RF energy, in order to reduce interference between terminals. A consequence of this is that it creates the most efficient use of the power supply of the terminals.
There are, also, other components of most conventional routing algorithms for ad-hoc, peer-to-peer radio systems that are generally related to the Quality of Service (QOS). The two major attributes of QoS are: The potential for delay, or latency, and the potential for bit errors (BER) during transmission. However, no present or prior system or algorithm has taken into consideration the impact of the battery life of the terminals, which, as stated above, should be a major and primary consideration for any network that consists of hand-held terminals, and especially for an ad-hoc, peer-to-peer radio system where batteries are used so much more as compared to conventional radio systems such as the cellular network, PCS's, and the like. Since hand-held terminals only have limited battery life in terms of trade off of size and weight, users do all that is possible in order to conserve their batteries, so that there will be sufficient life in them when they wish to use the device. As stated above, ad-hoc networks discharge a battery even more, even when the terminal owner is not using the terminal, since each terminal may also serve as a base station or a router or a link in the routing decision for connecting a call.
In above-mentioned commonly-owned U.S. Pat. No. 6,807,165, entitled “Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel”, each radio terminal of the ad-hoc radio system initially determines a routing table which typically includes a plurality of different routing paths to a gateway, which is also called an TAP (Intelligent Access Point), by means of other radio terminals of the ad-hoc radio system forming a service group (SG), which other radio terminals serves as nodes, or relays for connecting a source radio terminal to a gateway. After this initial route-mapping, the ad-hoc radio terminal will then determine the most optimal gateway with which to connect, if more than one gateway is available, which decision is based on the most optimal path to a chosen gateway that provides least-energy connection, as described in above-mentioned commonly-owned U.S. Pat. No. 6,807,165. Least-energy routing is most applicable and relevant to data calls, such as FTP and bulk file transfers. However, for voice and video transmissions, latency is a critical factor, whereby a routing path for voice and video may not necessarily be the most optimal as that for data transmissions.
Reference is also had to commonly-owned pending provisional patent application Ser. No. 60/297,769, filed on Jun. 14, 2001, entitled “Embedded Routing Algorithm under the Internet Protocol Routing Layer in a Software Architecture Protocol Stack”, which application is incorporated by reference herein. The protocol stack of the system of this application defines the various algorithms used in establishing the connection of a radio terminal of the ad-hoc, peer-to-peer radio system disclosed in the present invention within its neighborhood of other terminals, with a gateway, and for setting necessary parameters for setting up and receiving calls, and updating necessary routing, power-level, quality-of-service parameters, as well as other essential processes used in the ad-hoc system of the present invention.
The present invention, therefore, is directed to the provision of the consideration of the status of the battery-charge of each terminal forming a part or link of an ad-hoc, peer-to-peer radio system, whereby the routing algorithm and method by which a call from a terminal-source is connected to the terminal-destination or to an exterior, independent radio system and/or PSTN interconnected with the ad-hoc, peer-to-peer radio system in which the present invention is deployed, also takes into consideration the status of the battery of each terminal by which the routing of the outgoing call is to be connected.
In addition, the present invention also takes into consideration the class-of-service (CoS) of the call to be transmitted, whether it be data, voice, or video. Based on the CoS, the ad-hoc radio terminal will choose a routing path among those available to that ad-hoc radio terminal that best meets the criteria for the particular class, based on bit error rate (BER) and latency.